Typically, Thin Film Transistor (TFT) plays a very important role in an array substrate.
In conventional method of manufacturing a thin film transistor, in the process of depositing a source/drain metal layer and etching the source/drain metal layer so as to form source/drain electrodes, the source/drain metal layer is subject to one wet etching and one dry etching, wherein in the dry etching process, there are various drawbacks during etching the source and drain metallic layer corresponding to the channel region. For example, it is difficult for the dry etching apparatus to etch the metallic layer, the etching is not uniform, a great loss occurs to the apparatus, the yield is low and it is difficult to be applied for mass production.